Question

A compressor is used to bring saturated water vapor at 103 lbf/in.² up to 2000 lbf/in.², where the actual exit temperature is 1200 F. Find the isentropic compressor efficiency and the entropy generation. 

Answer 1

C.V. Compressor. Assume adiabatic and neglect kinetic energies

Energy Eq.  w = h₁ - h₂

Entropy Eq  s₂ = s₁ + s_gen

We have two different cases, the ideal and the actual compressor.

States: 1: h₁ = 1188.36 Btu/lbm, s₁ = 1.601 Btu/lbm R

2ac:  h_2,AC = 1598.6 Btu/lbm, s_2,AC = 1.6398 Btu/lbm R

2s: F.7.2 (P, s = s₁) h_2,s = 1535.1 Btu/lbm